1. Field of the Invention
The present invention relates generally to a method and system for detecting hidden dense objects in cargo containers, and more specifically to the detection of hidden dense objects using a comparison of actual and anticipated weight and mass distribution of individual cargo containers.
2. Description of the Related Art
Every year approximately seven million cargo containers carrying a large variety of goods originating everywhere in the world, arrive into the ports of the United States of America. At present only a minute percentage of these cargo containers are screened by various governmental agencies. Recent terrorism and homeland security concerns over the possibility of weapons of mass destruction (WMD) or materials used in making WMD, e.g., a so called “dirty bomb” (a conventional bomb made using radioactive material for the purpose of killing or infecting large numbers of people), being smuggled into the country, have highlighted the need and intensified the search for a system and method of screening this immense number of cargo containers.
In addition to not being able to screen large amounts of cargo containers, present technology such as nuclear detectors is typically used to sense possible radiological material inside the cargo containers. However, if the radiological material is well shielded, for example, by lead or other radiologically dense material, the nuclear detector may not detect the lethal contraband even if the container is screened. Accordingly, what is needed is a device that will sense anomalously dense materials inside the cargo or other types of containers, such as, for example, freight train cars, and screen a large number of containers in a very short time, for possible further investigation, for example, via an X-ray analysis, when the anomalously dense materials are detected in a cargo container being investigated.